Fluid flow meters are used to measure the volume of fluid flowing through a system. For example, water meters are used in residential and commercial environments being supplied with water by a public water utility.
A diverse spectrum of water metering technologies is being used today to meter water flow. One exemplarily technology is positive displacement water meters. Such technology may use oscillating pistons in communication with register technology that registers the volume of fluid flow by counting the number of times a chamber of a known volume is filled with water and emptied.
For positive displacement meters, water enters one side of the meter housing and flows into a measuring chamber to the flow measuring elements comprising a rotation piston. Due to a higher pressure at the input of the meter, water is pushed through the meter causing the piston to rotate causing a reciprocating motion forcing a second compartment to be emptied as a first compartment is filled. With each rotation of the piston, the same volume of water enters and leaves the measuring chamber. Typically, a magnetic element is associated with a rotating element to generate a varying magnetic field that is detected by register components.
To install the flow measuring elements in such a meter, the meter housing is associated with a removable cover or plate. Prior art meters use bolts and nuts to associate the cover to the meter housing. Using bolts and nuts not only increases assembly time, such components increase the meter's part count.
Embodiments of the disclosed inventions lower a meter's part count and simplify meter assembly by eliminating the use of bolts for associating a cover to such meter's housing.
Another area where residential water meters can be improved relates to backflow preventers and check valves. If the pressure of the water source fails and becomes lower than the pressure at a water consumer, water can backflow from the water consumer through the water meter and back into the water source. If such back flow is contaminated the water source becomes contaminated which is supplied to “downstream” consumers. Additionally, back flow from a residential consumer can cause the consumer's water heater to drain of all water thereby damaging such water heater.
Embodiments of the disclosed inventions relate to configuring a water meter's input and output ports with back flow preventers/check valves to prevent fluid flow from a fluid consumer to a fluid supply system.
Another problem that water meter manufacturers face is damage to the meter caused by over pressure conditions. If the pressure inside the water meter housing exceeds the rated water pressure, the water meter can be destroyed and/or the measuring elements may be damaged affecting the meter's accuracy. One phenomenon that can cause an over pressure condition is the freezing of the fluid inside the meter housing.
Embodiments of the present invention address such issues by designing in a “weakest link”. During over pressure conditions, the weakest link fails thereby releasing the pressure inside the meter housing protecting the remaining components. Preferably, replacing the weakest link results in the lowest repair costs compared to other meter components.